The COVID-19 outbreak posed significant challenges for teachers by forcing them to move from face-to-face teaching to online teaching. Against this background, teachers’ beliefs about, and practices of, online teaching became particularly important because they might influence teachers’ teaching effectiveness and children’s learning. However, little is known about the factors affecting teachers’ beliefs about, and practices of, online teaching during COVID-19. This study examined the associations of psychological distress and professional identity with perceived value of online courses and perceived quality of online teaching among 127 Chinese preschool teachers during COVID-19. Results showed that depression and loneliness were negatively associated with perceived value of online courses and perceived quality of online teaching, respectively, while professional identity was positively associated with both. Our findings highlight the unique roles of psychological distress and professional identity in shaping preschool teachers’ beliefs about, and practices of, online teaching during COVID-19. Policymakers should establish effective policies and guidelines to protect preschool teachers’ mental well-being and help alleviate their psychological distress, particularly depression and loneliness, in times of unforeseen disasters such as the pandemic. School leaders and teacher training professionals should prioritize professional identity as a crucial part of preschool teachers’ professional development during the COVID-19 outbreak.